Question

directions: select the correct longitudinal wave.
the four diagrams below represent particles of gas experiencing different longitudinal waves. which longitudinal wave has the greatest amplitude?

Explanation:

Step1: Recall Amplitude in Longitudinal Waves

In longitudinal waves (like sound in gas), amplitude is the maximum displacement of particles from their equilibrium position, related to the density difference (compression/rarefaction intensity). Greater amplitude means larger differences in particle clustering (more compressed regions and more rarefied regions).

Step2: Analyze Each Diagram

• First diagram: Particles have noticeable clusters (compressions) and spread-out areas (rarefactions), but check others.
• Second diagram: Particles are more uniformly distributed, less contrast in clustering.
• Third diagram: Particles seem sparse, less dense clustering.
• Fourth diagram: Wait, re - evaluate. Wait, the first diagram (top - most) has more distinct and intense compressions (dense particle groups) and rarefactions (sparser groups) compared to others. Wait, no, wait the bottom - most diagram? Wait, no, let's re - look. Wait, the key is: in longitudinal waves, amplitude is the maximum distance particles move from rest, so the diagram with the most "bunched" (compressed) and most "spread" (rarefied) regions has the greatest amplitude. The top - most diagram (first one) has more pronounced dense and sparse regions. Wait, no, maybe the bottom - most? Wait, no, let's correct. Wait, the first diagram (the top one) has particles with more distinct clusters (compressions) and more spread - out areas (rarefactions) than the second (which is more uniform), third (sparser), and the fourth? Wait, the fourth diagram has particles in groups, but the first diagram's particles have a larger range of density (more compressed and more rarefied). Wait, actually, the first diagram (top) has the greatest variation in particle density, meaning the greatest amplitude. Wait, but maybe I made a mistake. Wait, the correct approach: Amplitude in longitudinal waves is the maximum displacement, so the wave with the largest difference between compression (maximum particle density) and rarefaction (minimum particle density) has the greatest amplitude. So among the four, the first diagram (top - most) has the most dense compressions and most sparse rarefactions.

Wait, no, looking at the diagrams again:

• Diagram 1 (top): Particles have areas with many particles (compressions) and areas with few (rarefactions).
• Diagram 2: Particles are more evenly distributed, less contrast.
• Diagram 3: Particles are relatively sparse, less dense compressions.
• Diagram 4: Particles are in groups, but the density difference is less than diagram 1.

So the first diagram (top - most) has the greatest amplitude.

Answer:

The top - most diagram (the first diagram from the top)